Moet u CBD aan uw huisdier geven?april 21, 2020
Many of you pet parents out there may know from personal experience the level of confusion that exists in the veterinary community around cannabidiol (CBD) products for pets. In fact, many veterinarians are reluctant to even discuss the topic with their clients for legal reasons and because at the present time, there are many more questions than answers with regard to the effectiveness of CBD in veterinary patients with the variety of products on the market.
Research into CBD for dogs and cats is happening, but as veterinary journal dvm360 describes the situation:
“… research data is not what most veterinarians want to hear. They want to know about clinical usage. Unfortunately, the data is not yet translatable into reliable clinical information for all the claims made.
While over 23,000 scientific papers on cannabinoids in humans, lab animals and companion animals in 24 different species have been published, the jury is still out on exactly what CBD products are effective for and what they are not.”1
However, despite the reticence of the veterinary community to consider the use of cannabidiol, CBD products for dogs and cats are flooding the market as increasing numbers of pet parents search for nontoxic remedies for pain and other conditions in their animal companions.
I feel it’s extremely important that my veterinary colleagues take an active role to address their confusion and distrust around CBD. Many integrative practitioners, including me, have found this herbal remedy extremely beneficial in treating a multitude of medical and behavioral issues in our patients, and feel more pets should be provided the opportunity to experience those benefits as well.
Thankfully, my friend and colleague Dr. Rob Silver, author of “Medical Marijuana and Your Pet,” chief medical officer for Rx Vitamins for Pets, and a small animal veterinarian in Colorado, was invited to speak at a 2019 conference of conventional veterinarians about his experience and knowledge of CBD, including case-based information on its use in veterinary medicine.
But before we get into that, it’s important to have a basic understanding of CBD and its function in the body.
CBD and the Endocannabinoid System
CBD is a cannabinoid containing naturally occurring chemicals that act on the brain and body. The oil is produced from the cannabis plant and has no psychoactive properties like the THC (tetrahydrocannabinol) found in marijuana. Since it’s considered to have a wider range of medical benefits than THC, it can be a win-win for pets.
CBD is extracted from cannabis plants and processed as an isolate or as a full-spectrum oil combined with other related cannabinoids. CBD oils made with full-spectrum extracts are thought to have superior therapeutic effects vs. cannabidiol-only oil.
There are two common strains of cannabis in use today — hemp and marijuana. Hemp is a cannabis plant that contains less than 0.3 percent of THC; marijuana has more than 0.3 percent. CBD products for pets are typically sourced from hemp.
Humans, dogs, cats, and all creatures with a spinal column have an endocannabinoid system (ECS). The ECS was discovered fairly recently and named for the Cannabis sativa L. plant species due to the plant’s ability to dramatically effect it. According to dvm360:
“… the body makes its own (endo)cannabinoids as part of the nervous system, or at least as a partner to it. There are cannabinoid receptors in the brain, heart, lungs, liver, spleen, intestinal tract, muscles, bone, reproductive system and circulatory system, among others. There is some evidence to suggest that the endocannabinoid system is responsible for the ‘runner’s high‘ in people.”
The job of the ECS is to regulate functions such as eating, sleeping, relaxing, protecting, and forgetting by maintaining homeostasis via activators and receptors located in the central nervous system and immune system.
Cannabinoids function as messengers for the ECS, and according to Bark magazine, “… their effects depend on the receptors to which they bind. This is a very specific process; a receptor will only accept the particular compound for which it exists, and is unaffected by others.”2
Latest Info on CBD Dosing and Administration in Dogs and Cats
Before study results began to appear, the generally accepted therapeutic dose range for CBD in pets was 0.1 to 0.5 mg/kg twice daily, but according to Dr. Silver and Stephen Cital, co-founder of the Veterinary Cannabis Academy and director of education and development for ElleVet Sciences, it’s safe to go as high as 5 mg/kg twice daily.
A 2018 Cornell study actually shows that dosing as high as 8 mg/kg is safe,3 however, according to Cital, this dosage is neither cost-effective nor practical. He also notes that dosing range guidance has been updated to 0.1 to 2 mg/kg twice daily for dogs and cats based on the most recent data. According to Silver, as far as we know at this time, dosing for cats and dogs is the same.
Both Silver and Cital say patients can and do respond differently to standard dosages, perhaps because only animals with an endogenous deficiency in the endocannabinoid system respond to these products.
Most CBD given to pets at the present time is given orally. There are many other forms of CBD and routes of delivery (e.g., concentrates, topicals, transdermals, vaporizers, nebulizers, suppositories, capsules, tablets, soft chews, powders, biscuits, etc.), however, these are all still being studied in animals. Since bioavailability will be different for different routes, the recommendations for each will be different, and there are no guidelines yet.
Cital also notes that delivery either transdermally or via inhalation bypasses metabolism through the liver, so extra caution is warranted — especially since there is no research available yet in companion animals.
CBD and Pain Relief in Pets
In Silver’s experience, lower doses of CBD are often effective for neuropathic pain, but higher doses are typically required to alleviate discomfort in dogs and cats with inflammatory conditions such as osteoarthritis.
Cital recommends starting with 1 to 2 mg/kg twice daily regardless of the source of the pain, and titrating (adjusting the dose up or down) to achieve the desired effect. He also noted that nonsteroidal anti-inflammatory drugs (NSAIDs) and CBD can act synergistically, so use of both may lower the necessary dose of either.
Silver and other veterinarians he’s in contact with have found 0.5 mg/kg twice daily to be effective. He feels it’s wise to start at this lower dose, which may prove effective, to reduce the cost and amount of hemp extract used. He also says that using CBD together with opioids may allow for lower opioid doses, because CBD indirectly stimulates opioid receptors, producing an opioid-sparing effect.
CBD and Seizures
Silver makes the point that since THC itself is psychotropic, it is not considered an anti-seizure drug and has been reported to actually cause seizures. If this is the case, any THC in a CBD could potentially make a seizure patient worse, but studies are incomplete.
He cites a Colorado State University study of CBD at 2.5 mg/kg twice daily for refractory epilepsy in which some dogs experienced a 40% reduction in seizures,4 which Silver considers a not-very-impressive result. In my opinion, if your pet is among the 40% of animals that improve, it’s quite impressive and worth exploring as an adjunctive treatment. A new study at a higher dose (4.5 mg/kg twice daily) is underway.
He says that for uncomplicated seizures that are either infrequent or well-controlled with anti-convulsant drugs, veterinarians and pet owners are finding that 0.5 to 1.0 mg/kg of CBD twice daily can control them and even allow for reduced doses of anti-epileptic drugs in some cases.
CBD and Cancer
Cannabinoids appear to be able to fight cancer. Studies are underway, including a 3-year study at the University of Guelph’s Ontario Veterinary College (OVC) to explore the use of cannabis to treat canine bladder cancer.5
Silver cautions that many claims surrounding CBD and cancer are, so far, not based in evidence, however, researchers have discovered the presence of receptors on tumor cells for cannabinoids. He knows of a veterinary oncologist who treated a lingual (tongue) mass using only non-THC CBD at 0.5 mg/kg twice daily, and in six weeks the mass was reduced to “nearly nothing.”
Silver is also aware of a dog with an appendicular fibrosarcoma (a cancerous tumor of the leg) whose owners didn’t want to amputate. Treatment with nutraceuticals (not containing CBD) kept the tumor from growing for a year, at which point it started to grow again. So the dog was started on a 1:1 CBD:THC product and within three months the tumor had shrunk “dramatically.”
In another case Silver is aware of, a dog with an undifferentiated nasal carcinoma with bone lysis (damage to the bone from the cancer) was treated with a non-THC CBD product (0.4 mg/kg twice daily), and the tumor shrunk significantly over six weeks of treatment. The dog was still in remission 14 months later.
Both humans and animals can develop tolerance to chronic use of certain cannabinoids, including THC. When it comes to cannabinoids for cancer, when the treatment is stopped, the cancer may recur, indicating the animal has developed tolerance to CBD products.
Silver believes it’s important to alert pet parents to this phenomenon. “If you get a tumor response and stop, it will come back, and it will come back resistant,” he warns.6 It is also suspected that secondhand smoke may create THC tolerance in animals, but further studies are needed.
Side Effects of CBD in Pets
According to Silver, elevations in alkaline phosphatase (ALP) levels (ALP is a liver enzyme) with CBD use have been consistently noted in studies, but the “why” has yet to be studied. Diarrhea is a common side effect of CBD in pets, but at the present time it doesn’t appear there are any long-term adverse effects associated with bloodwork or urinalysis.7
THC toxicity in pets is a significant problem. “Too often in Colorado people are getting adult medical marijuana and giving it to pets,” says Silver. “Human dosages of these drugs will send pets to the ER. Hemp products do contain THC and can cause typical signs of THC toxicity, but they are more mild effects.”8
Choosing a CBD Product
Out of the hundreds, perhaps thousands of brands of CBD on the market, how does a pet parent or veterinarian go about choosing a high-quality product?
Both Silver and Cital recommend that you request a certificate of analysis from the manufacturer that indicates potency, per-dosing unit, all ingredients, and the presence of mycotoxins, metals or pesticides to determine if a product is reasonably safe. At this time, many manufacturers don’t provide this information or offer only a limited version, but hopefully this will improve with time.
I have also found substantial differences in effectiveness and potency not only between brands, but lots/batches, so if you didn’t think a brand you tried was effective, I recommend doing more research and choosing a different brand.
It’s important to keep in mind that anything that sounds too good to be true usually is, but hopefully, CBD products will one day have evidenced-based science behind them to prove their significant medicinal value.